Place the cocoa, water, and ½ cup sugar into a small saucepan. Bring to a boil over medium heat and whisk well. Turn heat to medium low and cook for one minute, whisking often. Remove from heat and add the chopped chocolate. Let sit for 5 minutes. Whisk well.
Place the cream cheese and salt into a medium bowl and use a silicone spatula to mix blend together.
In a small bowl, place the cornstarch. Measure two tablespoons of coconut milk out of the three cups and add to the cornstarch. Mix well and set aside.
Set up a large mixing bowl with about 3-4 cups ice cubes and 2-3 cups water. Have a gallon freezer bag ready for the ice cream.
Place the coconut milk, sugar and corn syrup into a small saucepan and heat over medium high heat until boiling. Turn heat down to medium low and cook for three minutes, whisking often. Remove from heat and turn heat down to low. Add the cornstarch mixture to the saucepan and stir. Place back on the heat over medium low and cook for two minutes, until mixture thickens.
Remove from heat and add about ½ cup of the hot mixture to the chocolate mixture and whisk well. Add another ½ cup and whisk in. Pour in the remaining mixture and whisk well. Pour into the gallon freezer bag, squeeze out the extra air, seal and let chill in the water bath for 30 minutes, adding more ice if it all melts.
Pour into the chilled container of your ice cream machine and spin and freeze until thick and creamy and the machine stops spinning. Chill for 3-4 hours.